47374_06_p43-66.qxd 2/9/07 8:40 AM Page 43
6
Chemical Quantities
16.00 amu
" 400.0 amu (4.000 ! 102 amu)
1 O atom
52.00 amu
" 7.80 ! 106 amu
b. 1.50 ! 105 Cr atoms !
1 Cr atom
19.00 amu
c. 6.24 ! 1020 F atoms !
" 1.19 ! 1022 amu
1 F atom
6.1
a. 25 O atoms !
6.2
a. 75 Ba atoms !
6.3
a. 540 amu Al !
6.4
a. 1.60 ! 104 amu Cu !
6.5
a. 1 atom S !
137.3 amu
" 1.030 ! 104 amu
1 Ba atom
30.97 amu
b. 2.80 ! 103 P atoms !
" 8.67 ! 104 amu
1 P atom
35.45 amu
" 3.24 ! 1027 amu
c. 9.15 ! 1025 Cl atoms !
1 Cl atom
1 atom Al
" 20 atoms Al
26.98 amu Al
1 atom Ag
" 2.73 ! 102 atoms Ag
b. 2.95 amu Ag !
107.9 amu Ag
1 atom Ne
c. 35 000 amu Ne !
" 1.7 ! 103 atoms Ne
20.18 amu Ne
1 atom Cu
" 2.52 ! 102 atoms Cu
63.55 amu Cu
1 atom Kr
" 76 atoms Kr
b. 6400 amu Kr !
83.80 amu Kr
1 atom Sr
c. 128 000 amu Sr !
" 1.46 ! 103 atoms Sr
87.62 amu Sr
32.07 amu
1 atom S
19.00 amu
6 atoms F !
1 atom F
40.08 amu
b. 1 atom Ca !
1 atom Ca
14.01 amu
2 atoms N !
1 atom N
16.00 amu
6 atoms O !
1 atom O
12.01 amu
c. 2 atoms C !
1 atom C
1.008 amu
6 atoms H !
1 atom H
16.00 amu
1 atom O !
1 atom O
"
"
32.07 amu
114.0 amu
146.1 amu (formula mass)
"
40.08 amu
"
28.02 amu
"
96.00 amu
164.10 amu (formula mass)
" 24.02 amu
"
"
6.048 amu
16.00 amu
46.07 amu (formula mass)
43
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 44
Chapter 6
12.01 amu
" 72.06 amu
1 atom C
1.008 amu
" 12.10 amu
12 atoms H !
1 atom H
16.00 amu
96.00 amu
6 atoms O !
"
1 atom O
180.16 amu (formula mass)
d. 6 atoms C !
6.6
6.7
44
35.45 amu
" 70.90 amu
1 atom Cl
16.00 amu
112.0 amu
"
7 atoms O !
1 atom O
182.9 amu (formula mass)
14.01 amu
b. 2 atoms N !
" 28.02 amu
1 atom N
12.01 amu
" 12.01 amu
1 atom C !
1 atom C
1.008 amu
" 8.064 amu
8 atoms H !
1 atom H
16.00 amu
48.00 amu
"
3 atoms O !
1 atom O
96.09 amu (formula mass)
12.01 amu
c. 3 atoms C !
" 36.03 amu
1 atom C
1.008 amu
" 8.064 amu
8 atoms H !
1 atom H
16.00 amu
48.00 amu
"
3 atoms O !
1 atom O
92.09 amu (formula mass)
12.01 amu
" 96.08 amu
d. 8 atoms C !
1 atom C
1.008 amu
" 10.08 amu
10 atoms H !
1 atom N
14.01 amu
" 56.04 amu
4 atoms N !
1 atom H
16.00 amu
32.00 amu
2 atoms O !
"
1 atom O
194.20 amu (formula mass)
a. 2 atoms Cl !
22.99 amu
" 45.98 amu
1 atom Na
32.07 amu
" 32.07 amu
1 atom S !
1 atom S
16.00 amu
48.00 amu
"
3 atoms O !
1 atom O
126.05 amu (formula mass)
26.98 amu
" 26.98 amu
b. 1 atom Al !
1 atom Al
16.00 amu
" 48.00 amu
3 atoms O !
1 atom O
1.008 amu
3.024 amu
"
3 atoms H !
1 atom H
78.00 amu (formula mass)
a. 2 atoms Na !
47374_06_p43-66.qxd 2/9/07 10:47 AM Page 45
Chemical Quantities
55.85 amu
" 55.85 amu
1 atom Fe
32.07 amu
1 atom S !
" 32.07 amu
1 atom S
16.00 amu
64.00 amu
4 atoms O !
"
1 atom O
151.92 amu (formula mass)
40.08 amu
d. 3 atoms Ca !
" 120.2 amu
1 atom Ca
30.97 amu
2 atoms P !
" 61.94 amu
1 atom P
16.00 amu
128.0 amu
"
8 atoms O !
1 atom O
310.1 amu (formula mass)
c. 1 atom Fe !
40.08 amu
" 40.08 amu
1 atom Ca
12.01 amu
1 atom C !
" 12.01 amu
1 atom Ca
16.00 amu
48.00 amu
3 atoms O !
"
1 atom O
100.09 amu (formula mass)
14.01 amu
b. 2 atoms N !
" 28.02 amu
1 atom N
1.008 amu
8 atoms H !
"
8.064 amu
1 atom H
32.07 amu
1 atom S !
" 32.07 amu
1 atom S
16.00 amu
64.00 amu
4 atoms O !
"
1 atom O
132.15 amu (formula mass)
65.41 amu
c. 3 atoms Zn !
" 196.2 amu
1 atom Zn
30.97 amu
2 atoms P !
" 61.94 amu
1 atom P
16.00 amu
128.0 amu
8 atoms O !
"
1 atom O
386.1 amu (formula mass)
195.1 amu
d. 1 atom Pt !
" 195.1 amu
1 atom Pt
14.01 amu
2 atoms N !
" 28.02 amu
1 atom N
1.008 amu
6 atoms H !
6.048 amu
"
1 atom H
35.45 amu
70.90 amu
2 atoms Cl !
"
1 atom Cl
300.1 amu
6.8
a. 1 atom Ca !
6.9
The mole is a unit that contains 6.022 ! 1023 particles (atoms, molecules of a covalent substance,
ions, or formula units of an ionic substance).
6.10 Avogadro’s number is 6.022 ! 1023, which is the number of particles in a mole.
6.11 One mol of chlorine atoms contains 6.022 ! 1023 atoms chlorine; 1 mol of chlorine molecules
contains 6.022 ! 1023 molecules chlorine, which is 2 ! 6.022 ! 1023 or 1.204 ! 1024 atoms
chlorine.
45
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 46
Chapter 6
6.12 1 mol of N atoms is 6.022 ! 1023 atoms of N, whereas 1 mol of N2 molecules is 6.022 ! 1023
molecules of N2. There are two N atoms in an N2 molecule, so there would be twice as many N
atoms in 1 mol of N2 molecules as in 1 mol of N atoms.
6.022 ! 1023 atoms C
" 3.01 ! 1023 C atoms
1 mol C
6.022 ! 1023 molecules SO2
" 7.71 ! 1023 SO2 molecules
b. 1.28 mol SO2 !
1 mol SO2
1 mol Fe
" 0.0867 mol Fe
c. 5.22 ! 1022 atoms Fe !
6.022 ! 1023 atoms Fe
1 mol C2H5OH
d. 8.50 ! 1024 molecules C2H5OH !
" 14.1 mol C2H5OH
6.022 ! 1023 molecules C2H5OH
6.13 a. 0.500 mol C !
6.022 ! 1023 atoms Li
" 2.7 ! 1024 Li atoms
1 mol Li
6.022 ! 1023 atoms CO2
b. 0.0180 mol CO2 !
" 1.08 ! 1022 CO2 molecules
1 mol CO2
1 mol Cu
c. 7.8 ! 1021 atoms Cu !
" 0.013 mol Cu
6.022 ! 1023 atoms Cu
1 mol C2H6
d. 3.754 ! 1023 molecules C2H6 !
" 0.6234 mol C2H6
6.022 ! 1023 molecules C2H6
6.14 a. 4.5 mol Li !
6.15 One mol H3PO4 molecules contains 3 mol H atoms, 1 mol P atoms, and 4 mol O atoms.
3 mol H
a. 2.00 mol H3PO4 !
" 6.00 mol H
1 mol H3PO4
4 mol O
b. 2.00 mol H3PO4 !
" 8.00 mol O
1 mol H3 PO4
1 mol P
6.022 ! 1023 atoms P
c. 2.00 mol H3PO4 !
!
" 1.20 ! 1024 P atoms
1 mol H3PO4
1 mol P
4 mol O
6.022 ! 1023 atoms O
d. 2.00 mol H3PO4 !
!
" 4.82 ! 1024 O atoms
1 mol H3PO4
1 mol O
6.16 1 mol (C3H5)2O molecules contains 6 mol C atoms, 10 mol H atoms, and 1 mol O atoms.
6 mol C
a. 0.185 mol (C3H5)2O !
" 1.11 mol C
1 mol (C3H5)2O
1 mol O
b. 0.185 mol (C3H5)2O !
" 0.185 mol O
1 mol (C3H5)2O
10 mol H
6.022 ! 1023 atoms H
c. 0.185 mol (C3H5)2O !
!
" 1.11 ! 1024 H atoms
1 mol (C3H5)2O
1 mol H
6 mol C
6.022 ! 1023 atoms C
d. 0.185 mol (C3H5)2O !
!
" 6.68 ! 1023 C atoms
1 mol (C3H5)2O
1 mol C
22.99 g Na
" 22.99 g Na
1 mol Na
35.45 g Cl
35.45 g Cl
"
1 mol Cl !
1 mol Cl
58.44 g NaCl (molar mass)
55.85 g Fe
b. 2 mol Fe !
" 111.7 g Fe
1 mol Fe
16.00 g O
48.00 g O
3 mol O !
"
1 mol O
159.7 g Fe2O3 (molar mass)
6.17 a. 1 mol Na !
46
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 47
Chemical Quantities
12.01g C
" 240.2 g C
1 mol C
1.008 g H
" 23.18 g H
23 mol H !
1 mol H
14.01 g N
14.01 g N
1 mol N !
"
1 mol N
277.4 g C2OH23N (molar mass)
d. One mol Al2(SO4)3 contains 2 mol Al, 3 mol S, and 12 mol O.
26.98 g Al
" 53.96 g Al
2 mol Al !
1 mol Al
32.07 g S
3 mol S !
" 96.21 g S
1 mol S
16.00 g O
192.0 g O
"
12 mol O !
1 mol O
342.2 g Al2(SO4)3
39.10 g K
" 39.10 g K
e. 1 mol K !
1 mol K
12.01 g C
" 48.04 g C
4 mol C !
1 mol C
16.00 g O
" 96.00 g O
6 mol O !
1 mol O
1.008 g H
5.040 g H
5 mol H !
"
1 mol H
188.18 g KC4H5O6 (molar mass)
c. 20 mol C !
f. One mol C16H19N3O5S contains 16 mol C, 19 mol H, 3 mol N, 5 mol O, and 1 mol S.
12.01 g C
" 192.2 g C
16 mol C !
1 mol C
1.008 g H
" 19.15 g H
19 mol H !
1 mol H
14.01 g N
" 42.03 g N
3 mol N !
1 mol N
16.00 g O
" 80.00 g O
5 mol O !
1 mol O
32.07 g S
32.07 g S
"
1 mol S !
1 mol S
365.5 g C16H19N3O5S
55.85 g Fe
6.18 a. 1 mol Fe !
" 55.85 g Fe
1 mol Fe
32.07 g S
" 32.07 g S
1 mol S !
1 mol S
16.00 g O
64.00 g O
"
4 mol O !
1 mol O
151.92 g (molar mass)
26.98 g Al
" 53.96 g Al
b. 2 mol Al !
1 mol Al
16.00 g O
48.00 g O
"
3 mol O !
1 mol O
101.96 g (molar mass)
47
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 48
Chapter 6
12.01 g C
" 84.07 g C
1 mol C
1.008 g H
"
5.040 g H
5 mol H !
1 mol H
14.01 g N
" 14.01 g N
1 mol N !
1 mol N
16.00 g O
" 48.00 g O
3 mol O !
1 mol O
32.07 g S
32.07 g S
"
1 mol S !
1 mol S
183.19 g (molar mass)
12.01 g C
" 36.03 g C
d. 3 mol C !
1 mol C
1.008 g H
" 8.064 g H
8 mol H !
1 mol H
16.00 g O
16.00 g O
"
1 mol O !
1 mol O
60.09 g (molar mass)
14.01 g H
" 28.02 g N
e. 2 mol N !
1 mol N
1.008 g H
" 8.064 g H
8 mol H !
1 mol H
12.01 g C
" 12.01 g C
1 mol C !
1 mol C
16.00 g O
48.00 g O
"
3 mol O !
1 mol O
96.09 g (molar mass)
65.41 g Zn
" 65.41 g Zn
f. 1 mol Zn !
1 mol Zn
12.01 g C
" 48.04 g C
4 mol C !
1 mol C
1.008 g H
"
6.048 g H
6 mol H !
1 mol H
16.00 g O
64.00 g O
4 mol O !
"
1 mol O
183.50 g (molar mass)
c. 7 mol C !
35.45 g Cl
" 70.90 g Cl2
1 mol Cl
12.01 g C
" 36.03 g C
b. 3 mol C !
1 mol C
1.008 g H
6 mol H !
" 6.048 g H
1 mol H
16.00 g O
48.00 g O
"
3 mol O !
1 mol O
90.08 g C3H6O3
24.31 g Mg
" 72.93 g Mg
c. 3 mol Mg !
1 mol Mg
30.97 g P
2 mol P !
" 61.94 g P
1 mol P
16.00 g O
128.0 g O
"
8 mol O !
1 mol O
262.9 g C3H6O3
6.19 a. 2 mol Cl !
48
47374_06_p43-66.qxd 2/9/07 10:47 AM Page 49
Chemical Quantities
26.98 g Al
1 mol Al
19.00 g F
3 mol F !
1 mol F
12.01 g C
e. 2 mol C !
1 mol C
1.008 g H
4 mol H !
1 mol H
35.45 g Cl
2 mol Cl !
1 mol Cl
118.7 g Sn
f. 1 mol Sn !
1 mol Sn
19.00 g F
2 mol F !
1 mol F
d. 1 mol Al !
" 26.98 g Al
"
57.00 g O
83.98 g AlF3
" 24.02 g C
"
"
4.032 g H
70.90 g Cl
98.95 g C2H4Cl2
" 118.7 g Sn
"
38.00 g F
156.7 g SnF2
16.00 g O2
" 32.00 g O2
1 mol O
39.10 g K
1 mol K !
" 39.10 g Mg
1 mol K
1.008 g H
2 mol H !
"
2.016 g H
1 mol H
30.97 g P
1 mol P !
" 30.97 g P
1 mol P
16.00 g O
64.00 g
4 mol O !
"
1 mol O
136.09 g
55.85 g Fe
1 mol Fe !
" 55.85 g Fe
1 mol Fe
35.45 g Cl
3 mol Cl !
" 106.4 g Cl
1 mol Cl
16.00 g O
192.0 g O
12 mol O !
"
1 mol O
354.3 g
12.01 g C
4 mol C !
" 48.04 g C
1 mol C
1.008 g H
8 mol H !
"
8.064 g H
1 mol H
16.00 g O
64.00 g
4 mol O !
"
1 mol O
120.10 g
69.72 g Ga
2 mol Ga !
" 139.4 g Ga
1 mol Ga
12.01 g C
3 mol C !
" 36.03 g C
1 mol C
16.00 g O
144.0 g O
9 mol O !
"
1 mol O
319.4 g
39.10 g K
1 mol K !
" 39.10 g K
1 mol K
79.90 g Br
1 mol Br !
" 79.90 g Br
1 mol Br
16.00 g O
64.00 g O
4 mol O !
"
1 mol O
183.00 g
6.20 a. 2 mol O !
b.
c.
d.
e.
f.
49
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 50
Chapter 6
22.99 g Na
1 mol Na
40.08 g Ca
2.80 mol Ca !
1 mol Ca
44.01 g CO2
0.125 mol CO2 !
1 mol CO2
105.99 g Na2CO3
0.0485 mol Na2CO3 !
1 mol Na2CO3
137.32
g PCl3
7.14 ! 102 mol PCl3 !
1 mol PCl3
6.21 a. 1.50 mol Na !
b.
c.
d.
e.
" 34.5 g Na
" 112 g Ca
" 5.50 g CO2
" 5.14 g Na2CO3
" 9.80 ! 104 g PCl3
26.98 g Al
1 mol Al
63.55 g Cu
0.75 mol Cu !
1 mol Cu
184.11 g MgBr2
3.52 mol MgBr2 !
1 mol MgBr2
46.07 g C2H6O
0.145 mol C2H6O !
1 mol C2H6O
132.15 g (NH4)2SO4
2.08 mol (NH4)2SO4 !
1 mol (NH4)2SO4
6.22 a. 5.12 mol Al !
b.
c.
d.
e.
20.18 g Ne
1 mol Ne
253.8 g I2
0.150 mol I2 !
1 mol I2
61.98 g Na2O
0.150 mol Na2O !
1 mol Na2O
164.10 g Ca(NO3)2
0.150 mol Ca(NO3)2 !
1 mol Ca(NO3)2
86.17 g C6H14
0.150 mol C6H14 !
1 mol C6H14
6.23 a. 0.150 mol Ne !
b.
c.
d.
e.
28.02 g N2
1 mol N2
80.07 g SO3
2.28 mol SO3 !
1 mol SO3
90.08 g C3H6O3
2.28 mol C3H6O3 !
1 mol C3H6O3
146.35 g Mg(HCO3)2
2.28 mol Mg(HCO3)2 !
1 mol Mg(HCO3)2
146.07 g SF6
2.28 mol SF6 !
1 mol SF6
6.24 a. 2.28 mol N2 !
b.
c.
d.
e.
1 mol Ag
107.9 g Ag
1 mol C
b. 0.188 g C !
12.01 g C
1 mol NH3
c. 15.0 g NH3 !
17.03 g NH3
6.25 a. 82.0 g Ag !
50
" 138 g Al
" 48 g Cu
" 648 g MgBr2
" 6.68 g C2H6O
" 275 g (NH4)2SO4
" 3.03 g Ne
" 38.1 g I2
" 9.30 g Na2O
" 24.6 g Ca(NO3)2
" 12.9 g C6H14
" 63.9 g N2
" 183 g SO3
" 205 g C3H6O3
" 334 g Mg(HCO3)2
" 333 g SF6
" 0.760 mol Ag
" 0.0240 mol C
" 0.881 mol NH3
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 51
Chemical Quantities
1 mol C3H8
44.09 g C3H8
1 mol Fe2O3
e. 245 g Fe2O3 !
159.7 g Fe2O3
d. 7.25 g C3H8 !
1 mol Ni
58.69 g Ni
1 mol K
144 g K !
39.10 g K
1 mol H2O
6.4 g H2O !
18.02 g H2O
1 mol BaSO4
308 g BaSO4 !
233.4 g BaSO4
1 mol C6H12O6
252.8 g C6H12O6 !
180.16 g C6H12O6
6.26 a. 85.2 g Ni !
b.
c.
d.
e.
1 mol He
4.003 g He
1 mol O2
25.0 g O2 !
32.00 g O2
1 mol Al(OH)3
25.0 g Al(OH)3 !
78.00 g Al(OH)3
1 mol Ga2S3
25.0 g Ga2S3 !
235.65 g Ga2S3
1 mol C4H10
25.0 g C4H10 !
58.12 g C4H10
6.27 a. 25.0 g He !
b.
c.
d.
e.
1 mol He
4.003 g He
1 mol SnO2
4.00 g SnO2 !
150.7 g SnO2
1 mol Cr(OH)3
4.00 g Cr(OH)3 !
103.02 g Cr(OH)3
1 mol Ca3N2
4.00 g Ca3N2 !
148.28 g Ca3N2
1 mol C6H8O6
4.00 g C6H8O6 !
176.12 g C6H8O6
6.28 a. 4.00 g He !
b.
c.
d.
e.
" 0.164 mol C3H8
" 1.53 mol Fe2O3
" 1.45 mol Ni
" 3.68 mol K
" 0.36 mol H2O
" 1.32 mol BaSO4
" 1.403 mol C6H12O6
" 6.25 mol He
" 0.781 mol O2
" 0.320 mol Al(OH)3
" 0.106 mol Ga2S3
" 0.430 mol C4H10
" 0.999 mol He
" 0.0265 mol SnO2
" 0.0388 mol Cr(OH)3
" 0.0270 mol Ca3N2
" 0.0227 mol C6H8O6
1 mol C
6.022 ! 1023 C atoms
!
" 1.25 ! 1024 C atoms
12.01 g C
1 mol C
6.022 ! 1023 C atoms
" 4.14 ! 1024 C atoms
0.688 mol C !
1 mol C
1 mol C3H8
3 mol C
6.022 ! 1023 C atoms
!
!
"
275 g C3H8 !
44.09 g C3H8
1 mol C3H8
1 mol C
1.13 ! 1025 C atoms
2 mol C
6.022 ! 1023 C atoms
!
" 2.22 ! 1024 C atoms
1.84 mol C2H6O !
1 mol C2H6O
1 mol C
1 atom C
7.5 ! 1024 molecules CH4 !
" 7.5 ! 1024 C atoms
1 molecule CH4
6.29 a. 25.0 g C !
b.
c.
d.
e.
51
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 52
Chapter 6
2 mol N
6.022 ! 1023 N atoms
!
" 9.09 ! 1023 N atoms
1 mol N2
1 mol N
1 mol NaNO3
1 mol N
6.022 ! 1023 N atoms
!
!
"
b. 0.82 g NaNO3 !
85.00 g NaNO3
1 mol NaNO3
1 mol N
5.8 ! 1021 N atoms
6.30 a. 0.755 mol N2 !
1 mol N2O
2 mol N
6.022 ! 1023 N atoms
!
!
" 1.09 ! 1024 N atoms
44.02 g N2O
1 mol N2O
1 mol N
1 mol N
6.022 ! 1023 N atoms
d. 6.24 ! 10 #3 mol NH3 !
!
" 3.76 ! 1021 N atoms
1 mol NH3
1 mol N
2 atoms N
e. 1.4 ! 1022 molecules N2O4 !
" 2.8 ! 1022 N atoms
1 molecule N2O4
c. 40.0 g N2O !
44.09 g C3H8
" 66.1 g propane (C3H8)
1 mol C3H8
1 mol C3H8
b. 34.0 g C3H8 !
" 0.771 mol propane (C3H8)
44.09 g C3H8
3 mol C
12.01 g C
c. 0.771 mol C3H8 !
!
" 27.8 g C
1 mol C3H8
1 mol C
1 mol C3H8
8 mol H
6.022 ! 1023 atoms H
d. 0.254 g C3H8 !
!
!
44.09 g C3H8
1 mol C3H8
1 mol H
22
" 2.78 ! 10 atoms H
6.31 a. 1.50 mol C3H8 !
6.32 a.
b.
c.
d.
0.203 mol S
4.5 ! 1024 atoms H
50.3 g C
4.75 ! 1023 C atoms
24.31 g Mg
" 24.31 g Mg
1 mol Mg
19.00 g F
38.00 g F
"
2 mol F !
1 mol F
62.31 g MgF2
24.31 g Mg
! 100% " 39.01% Mg
62.31 g MgF2
38.00 g F
! 100% " 60.99% F
62.31 g MgF2
40.08 g Ca
b. 1 mol Ca !
" 40.08 g Ca
1 mol Ca
16.00 g O
2 mol O !
" 32.00 g O
1 mol O
1.008 g H
2.016 g H
"
2 mol H !
1 mol H
74.10 g Ca(OH)2
40.08 g Ca
! 100% " 54.09% Ca
74.10 g Ca(OH)2
32.00 g O
! 100% " 42.18% O
74.10 g Ca(OH)2
2.016 g H
! 100% " 2.72% H (rounded to 0.01%)
74.10 g Ca(OH)2
6.33 a. 1 mol Mg !
52
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 53
Chemical Quantities
12.01 g C
" 48.04 g C
1 mol C
1.008 g H
8 mol H !
"
8.06 g H (rounded to 0.01%)
1 mol H
16.00 g O
64.00 g O
"
4 mol O !
1 mol O
120.10 g C4H8O4
48.04 g C
! 100% " 40.00% C
120.10 g C4H8O4
8.064 g H
! 100% "
6.71% H (rounded to 0.01%)
120.10 g C4H8O4
64.00 g O
! 100% " 53.29% O
120.10 g C4H8O4
14.01 g N
d. 3 mol N !
" 42.03 g N
1 mol N
1.008 g H
" 12.10 g H
12 mol H !
1 mol H
30.97 g P
1 mol P !
" 30.97 g P
1 mol P
16.00 g O
64.00 g O
"
4 mol O !
1 mol O
149.10 g C4H8O4
43.03 g N
! 100% " 28.19% N
149.10 g C4H8O4
12.10 g N
! 100% "
8.12% H (rounded to 0.01%)
149.10 g C4H8O4
30.97 g P
! 100% " 20.77% P
149.10 g C4H8O4
64.00 g O
! 100% " 42.92% O
149.10 g C4H8O4
12.01 g C
e. 17 mol C !
" 204.2 g C
1 mol C
1.008 g H
" 19.15 g H
19 mol H !
1 mol H
14.01 g N
1 mol N !
" 14.01 g N
1 mol N
16.00 g O
48.00 g O
"
3 mol O !
1 mol O
285.3 g C17H19NO3
204.2 g C
! 100% " 71.56% C
285.3 g C17H19NO3
19.15 g H
! 100% "
6.71% H (rounded to 0.01%)
285.3 g C17H19NO3
14.01 g N
! 100% "
4.91% N (rounded to 0.01%)
285.3 g C17H19NO3
48.00 g O
! 100% " 16.82% O
285.3 g C17H19NO3
c. 4 mol C !
53
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 54
Chapter 6
6.34 a.
b.
c.
d.
e.
36.11% Ca; 63.89% Cl
17.55% Na; 39.70% Cr; 42.75% O
18.01% C; 2.27% H; 79.73% Cl
38.76% Ca; 19.97% P; 41.27% O
75.99% C; 12.76% H; 11.25% O
14.01 g N
" 28.02 g N
1 mol N
16.00 g O
80.00 g O
"
5 mol O !
1 mol O
108.20 g N2O5
28.02 g N
! 100% " 25.94% N
108.20 g N2O5
14.01 g N
" 28.02 g N
2 mol N !
1 mol H
1.008 g H
4 mol H !
" 4.032 g H
1 mol H
16.00 g O
48.00 g O
"
3 mol O !
1 mol O
80.05 g NH4NO3
28.02 g N
! 100% " 35.00% N
80.05 g NH4NO3
12.01 g C
" 24.02 g C
2 mol C !
1 mol C
1.008 g H
8 mol H !
" 8.064 g H
1 mol H
14.01 g N
28.02 g N
"
3 mol N !
1 mol N
60.10 g C2H8N2
28.02 g N
! 100% " 46.62% N
60.10 g C2H8N2
12.01 g C
" 108.0 g C
9 mol C !
1 mol C
1.008 g H
" 15.12 g H
15 mol H !
1 mol H
14.01 g N
" 70.05 g N
5 mol N !
1 mol N
16.00 g O
16.00 g O
"
1 mol O !
1 mol O
209.3 g C9H15N5O
70.05 g N
! 100% " 33.48% N
209.3 g C9H15N5O
12.01 g C
" 168.1 g C
14 mol C !
1 mol C
1.008 g H
" 22.18 g H
22 mol H !
1 mol H
14.01 g N
" 28.02 g N
2 mol N !
1 mol N
16.00 g O
16.00 g O
"
1 mol O !
1 mol O
234.3 g C14H22N2O
28.02 g N
! 100% " 11.96% N
234.3 g C14H22N2O
6.35 a. 2 mol N !
b.
c.
d.
e.
54
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 55
Chemical Quantities
6.36 a. 22.58% S
d. 41.04% S
b. 64.07% S
e. 12.81% S
c. 40.05% S
1 mol N
" 0.255 mol N
14.01 g N
1 mol O
" 0.128 mol O (smaller number of moles)
2.04 g O !
16.00 g O
0.128 mol O
0.255 mol N
" 1.99 mol N : 2
" 1.00 mol O
0.128
0.128
Empirical formula " N2O
1 mol C
b. 7.00 g C !
" 0.583 mol C (smaller number of moles)
12.01 g C
1 mol H
" 1.74 mol H
1.75 g H !
1.008 g H
0.583 mol C
1.74 mol H
" 1.00 mol C
" 2.98 mol H : 3
0.583
0.583
Empirical formula " CH3
1 mol H
c. 0.175 g H !
" 0.174 mol H
1.008 g H
1 mol N
" 0.174 mol N (smaller number of moles)
2.44 g N !
14.01 g N
1 mol O
" 0.524 mol O
8.38 g O !
16.00 g O
0.174 mol H
0.174 mol N
" 1.00 mol H
" 1.00 mol N
0.174
0.174
0.524 mol O
" 3.01 mol O
Empirical formula " HNO3
0.174
1 mol Ca
d. 2.06 g Ca !
" 0.0514 mol Ca
1.008 g Ca
1 mol Cr
" 0.0512 mol Cr (smaller number of moles)
2.66 g Cr !
52.00 g Cr
1 mol O
" 0.205 mol O
3.28 g O !
16.00 g O
0.0514 mol Ca
0.0512 mol Cr
" 1.00 mol Ca
" 1.00 mol Cr
0.0512
0.0512
0.205 mol O
" 4.00 mol O
Empirical formula " CaCrO4
0.0512
6.37 a. 3.57 g N !
6.38 a. Ag2S
b. Na2O
c. NaHSO4
d. K3PO4
6.39 11.44 g compound (S and F) # 2.51 g S " 8.93 g F
1 mol S
" 0.0783 mol S (smaller number of moles)
2.51 g S !
32.07 g S
1 mol F
" 0.470 mol F
8.93 g F !
19.00 g F
0.0783 mol S
0.470 mol F
" 1.00 mol S
" 6.00 mol F
0.0783 mol
0.0783
Empirical formula " SF6
55
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Chapter 6
6.40 Fe2O3
1 mol K
" 1.81 mol K
39.01 g K
1 mol S
" 0.907 mol S (smaller number of moles)
29.1 g S !
32.07 g S
0.907 mol S
1.81 mol K
" 2.00 mol K
" 1.00 mol S
0.907
0.907
Empirical formula " K2S
1 mol Ga
" 0.789 mol Ga (smaller number of moles)
55.0 g Ga !
69.72 g Ga
1 mol F
" 2.36 mol F
45.0 g F !
19.00 g F
0.789 mol S
2.36 mol F
" 1.00 mol Ga
" 2.99 mol F : 3 F
0.789
0.789
Empirical formula " GaF3
1 mol B
" 2.87 mol B (smaller number of moles)
31.0 g B !
10.81 g B
1 mol O
" 4.31 mol O
69.0 g O !
16.00 g O
4.31 mol O
2.87 mol B
" 1.00 mol B
" 1.50 mol O
2.87
2.87
1.00 mol B ! 2 " 2.00 mol B
1.50 mol O ! 2 " 3.00 mol O
Empirical formula " B2O3
1 mol Li
" 2.71 mol Li
18.8 g Li !
6.941 g Li
1 mol C
" 1.36 mol C (smaller number of moles)
16.3 g C !
12.01 g C
1 mol O
" 4.06 mol O
64.9 g O !
16.00 g O
2.71 mol Li
1.36 mol C
" 1.99 mol Li : 2 Li
" 1.00 mol C
1.36
1.36
4.06 mol O
" 2.98 mol : 3 O
Empirical formula " Li2CO3
1.36
1 mol C
1 mol H
51.7 g C !
" 4.31 mol C
" 6.85 mol H
6.90 g H !
12.01 g C
1.008 g H
1 mol O
" 2.58 mol O (smaller number of moles)
41.3 g O !
16.00 g O
4.31 mol C
6.85 mol H
" 1.67 mol C
" 2.66 mol H
2.58
2.58
2.58 mol O
" 1.00 mol O
2.58
1.67 mol C ! 3 " 5.01 mol C : 5 C 2.66 mol H ! 3 " 7.98 mol H : 8 H
1.00 mol O ! 3 " 3.00 mol O
Empirical formula " C5H8O3
6.41 a. 70.9 g K !
b.
c.
d.
e.
56
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 57
Chemical Quantities
6.42 a. CaS
6.43 a.
b.
c.
d.
e.
HO
C3H2
C5H8O
C3H6N2
CH2NO
6.44 a. C2H2O
b. BaF2
c. Zn3P2
d. Na2S2O3
2H % 2 " 1H and 2O % 2 " 1O
18C % 6 " 3C and 12H % 6 " 2
10C % 2 " 5C
16H % 2 " 8H
9C % 3 " 3C
18H % 3 " 6H
2C % 2 " 1C
4H % 2 " 2H
b. CH2O
c. B3H5
e. C3H4Cl4
2O % 2 " 1O
6N % 3 " 2N
2N % 2 " 1N
d. CCl
2O % 2 " 1O
e. C6H4O3
6.45 Mass of CH2O " 12.01 $ 2(1.008) $ 16.00 " 30.03 g
180 g (molar mass)
"6
30.03 g (empirical mass)
CH2O ! 6 " C6H12O6
6.46 C8H10N4O2
6.47 Mass of empirical formula CH " 12.01 $ 1.008 " 13.02 g
78 g (molar mass)
Benzene
" 6.0 CH ! 6 " C6H6
13.02 g (empirical mass)
26 g (molar mass)
" 2.0 CH ! 2 " C2H2
Acetylene
13.02 g (mass of empirical formula)
6.48 Mass of empirical formula CHO " 12.01 $ 1.008 $ 16.00 " 29.02g
58 g (molar mass)
Glyoxyl
" 2.0 CHO ! 2 " C2H2O2
29.02 g (empirical mass)
116.1 g (molar mass)
Maleic acid
" 4.0 CHO ! 4 " C4H4O4
29.02 g (mass of empirical formula)
174.1 g (molar mass)
" 6.0 CHO ! 6 " C6H6O6
Acontic acid
29.02 g (mass of empirical formula)
6.49 In 100 g of compound, there is 48.64 g C, 8.16 g H, and 43.20 g O.
1 mol C
" 4.050 mol C
Moles of C " 48.64 g C !
12.01 g C
1 mol H
" 8.10 mol H
Moles of H " 8.16 g H !
1.008 g H
1 mol O
" 2.70 mol O (smaller number of moles)
Moles of O " 43.20 g O !
16.00 g O
8.10 mol H
4.050 mol C
" 1.50 mol C
" 3.00 mol H
2.70
2.70
2.70 mol O
" 1.00 mol O
2.70
1.50 mol C ! 2 " 3.00 mol C 3.00 mol O ! 2 " 6.00 mol H 1.00 mol O ! 2 " 2.00 mol O
Empirical formula " C3H6O2
Mass of C3H6O2 " 3 ! 12.01 $ 6 ! 1.008 $ 2 ! 16.00 " 74.08 g
148 g (molar mass)
" 2.00
74.08 g (mass of empirical formula)
2 ! (Empirical formula C3H6O2) " Molecular formula C6H12O4
57
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Chapter 6
6.50 The empirical formula is C2H3Cl3O2, and the molecular formula is C2H3Cl3O2.
6.51 In 100 g of compound, there are 54.14 g C, 4.80 g H, and 38.06 g O.
1 mol C
" 4.758 mol C
Moles of C " 54.14 g C !
12.01 g C
1 mol H
" 4.76 mol H
Moles of H " 4.80 g H !
1.008 g H
1 mol O
" 2.379 mol O (smaller number of moles)
Moles of O " 38.06 g O !
16.00 g O
4.76 mol H
4.758 mol C
" 2.00 mol C
" 2.00 mol H
2.379
2.379
2.379 mol O
" 1.00 mol O
2.379
Empirical formula " C2H2O1
Mass of C2H2O1 " 2 ! 12.01 $ 2 ! 1.008 $ 1 ! 16.00 " 42.04 g
168.1 g (molar mass)
" 3.99 : 4.00
42.08 g (mass of empirical formula)
4 ! (Empirical formula C2H2O) " Molecular formula C8H8O4
6.52 The empirical formula is CH2O, and the molecular formula is C3H6O3.
6.53 In 100 g of compound, there are 74.0 g C and 8.7 g H. 100 g # (74.0 g $ 8.7 g) " 17.3 g N
1 mol C
" 6.16 mol C
Moles of C " 74.0 g C !
12.01 g C
1 mol H
" 8.6 mol H
Moles of H " 8.7 g H !
1.008 g H
1 mol N
" 1.23 mol N (smallest number of moles)
Moles of N " 17.3 g N !
14.01 g N
8.6 mol H
6.16 mol C
" 5.01 mol C
" 7.0 mol H
1.23
1.23
1.23 mol N
" 1.00 mol N
1.23
Empirical formula " C5H7N1
Mass of C5H7N1 " 5 ! 12.01 $ 7 ! 1.008 $ 1 ! 14.01 " 81.12 g
162 g (molar mass)
" 2.00
81.12 g (mass of empirical formula)
2 ! (Empirical formula C5H7N) " Molecular formula C10H14N2
6.54 The empirical formula is CHN, and the molecular formula is C5H5N5.
6.55 a. C10H8N2O2S2 % 2 " C5H4NOS (empirical formula)
12.01 g C
" 120.1 g C
b. 10 mol C !
1 mol C
1.008 g H
" 8.064 g H
8 mol H !
1 mol H
14.01 g N
" 28.02 g N
2 mol N !
1 mol N
16.00 g O
" 32.00 g O
2 mol O !
1 mol O
58
47374_06_p43-66.qxd 2/9/07 10:47 AM Page 59
Chemical Quantities
32.07 g S
64.14 g S
"
1 mol S
252.3 g C10H8N2O2S2
120.1 g C
! 100 " 47.60% C
252.3 g C10H8N2O2S2
8.064 g H
! 100 " 3.20% H (rounded to 0.01%)
252.3 g C10H8N2O2S2
28.04 g N
! 100 " 11.10% N
252.3 g C10H8N2O2S2
32.00 g O
! 100 " 12.68% O
252.3 g C10H8N2O2S2
64.14 g S
! 100 " 25.42% S
252.3 g C10H8N2O2S2
1 mol C10H8N2O2S2
10 mol C
c. 25.0 g C10H8N2O2S2 !
!
!
252.3 g C10H8N2O2S2
1 mol C10H8N2O2S2
6.022 ! 1023 C atoms
" 5.97 ! 1023 C atoms
1 mol C
1 mol N
1 mol C10H8N2O2S2
d. 8.2 ! 1024 N atoms !
!
"
23
6.022 ! 10 N atoms
2 mol N
6.8 mol C10H8N2O2S2
2 mol S !
6.56 a. 15.51% O
c. 1.13 g hydrogen
b. 1.61 ! 1022 carbon atoms
d. 1.29 ! 1022 hydrogen atoms
6.57 a.
b.
c.
d.
S2Cl2
SCl
2 mol S ! 32.07 g/mol S # 2 mol Cl ! 35.45 g/mol Cl " 135.04 g (molar mass)
2 mol S ! 32.07 g/mol S " 64.14 g S
64.14 g S/135.04 g S2Cl2 ! 100% " 47.50% S
2 mol Cl ! 35.45 g/mol Cl " 70.90 g Cl
70.90 g Cl/135.04 g S2Cl2 ! 100% " 52.50% Cl
6.58 a.
b.
c.
d.
C6H6
CH
6 mol C ! 12.01 g/mol C # 6 mol H ! 1.008 g/mol H " 78.11 g (molar mass)
6 mol C ! 12.01 g/mol C " 72.06 g C
72.06 g C/72.06 g C6H6 ! 100% " 92.25% C
6 mol H ! 1.008 g/mol H " 6.048 g H
6.048 g H/72.06 g C6H6 ! 100% " 7.946% H
6.59 a. 1 Fe atom !
1 S atom !
4 O atoms !
b. 1 Ca atom !
2 I atoms !
6 O atoms !
55.85 amu
1 Fe atom
32.07 amu
1 S atom
16.00 amu
1 O atom
40.08 amu
1 Ca atom
126.9 amu
1 I atom
16.00 amu
1 O atom
" 55.85 amu
" 32.07 amu
"
64.00 amu
151.92 amu
"
40.08 amu
" 253.8 amu
"
96.00 amu
389.9 amu
59
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 60
Chapter 6
12.01 amu
" 60.05 amu
1 C atom
1.008 amu
"
8.064 amu
8 H atoms !
1 H atom
14.01 amu
" 14.01 amu
1 N atom !
1 N atom
22.99 amu
" 22.99 amu
1 Na atom !
1 Na atom
16.00 amu
64.00 amu
"
4 O atoms !
1 O atom
169.11 amu
12.01 amu
" 72.06 amu
d. 6 C atoms !
1 C atom
1.008 amu
" 12.10 amu
12 H atoms !
1 H atom
16.00 amu
32.00 amu
2 O atoms !
"
1 O atom
116.16 amu
c. 5 C atoms !
6.60 a. 146.35 g/mol
b. 248.0 g/mol
c. 282.5 g/mol
39.10 g K
" 78.20 g K
1 mol K
52.00 g Cr
1 mol Cr !
" 52.00 g Cr
1 mol Cr
16.00 g O
64.00 g O
"
4 mol O !
1 mol O
194.20 g K2CrO4
78.20 g K
! 100% " 40.27% K
194.20 g K2CrO4
52.00 g Cr
! 100% " 26.78% Cr
194.20 g K2CrO4
64.00 g O
! 100% " 32.96% O
194.20 g K2CrO4
26.98 g Al
" 26.98 g Al
b. 1 mol Al !
1 mol Al
1.008 g H
"
3.024 g H
3 mol H !
1 mol H
12.01 g C
3 mol C !
" 36.03 g C
1 mol C
16.00 g O
144.0 g O
"
9 mol O !
1 mol O
210.0 g Al(HCO3)3
26.98 g Al
! 100% " 12.85% Al
210.0 g Al(HCO3)3
3.024 g H
! 100% " 1.44% H (rounded to 0.01%)
210.0 g Al(HCO3)3
36.03 g C
! 100% " 17.16% C
210.0 g Al(HCO3)3
144.0 g O
! 100% " 68.57% O
210.0 g Al(HCO3)3
6.61 a. 2 mol K !
60
d. 358.4 g/mol
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 61
Chemical Quantities
12.01 g C
1.008 g H
"
72.06 g
" 12.10 g
12 mol H !
1 mol C
1 mol H
16.00 g O
96.00 g
"
6 mol O !
1 mol O
180.16 g
72.06 g C
! 100% " 40.00% C
180.16 g C6H12O6
96.00 g O
! 100% " 6.71% H (rounded to 0.01%)
180.16 g C6H12O6
96.00 g O
! 100% " 53.29% O
180.16 g C6H12O6
c. 6 mol C !
6.62 a. 43.64% P
b. 45.93% P
c. 19.97% P
12.01 g C
" 36.03 g C
1 mol C
1.008 g H
6 mol H !
" 6.048 g H
1 mol H
16.00 g O
48.00 g O
"
3 mol O !
1 mol O
90.08 g C3H6O3
48.00 g O
! 100 " 53.29% O
90.08 g C3H6O3
6.63 a. 3 mol C !
1 mol C3H6O3
3 mol C
6.022 ! 1023 C atoms
!
!
"
90.08 g C3H6O3
1 mol C3H6O3
1 mol C
2.51 ! 1024 C atoms
1 mol H
1 mol C3H6O3
90.08 g C3H6O3
!
!
" 52.1 g C3H6O3
c. 3.50 g H !
1.008 g H
6 mol H
1 mol C3H6O3
d. C3H6O3 % 3 " CH2O (empirical formula)
b. 125 g C3H6O3 !
6.64 a.
b.
c.
d.
21.20% N
3.6 ! 1024 hydrogen atoms
47.8 g oxygen
10.3 g ammonium sulfate
12.01 g C
" 108.01 g C
1 mol C
1.008 g H
8 mol H !
"
8.064 g H
1 mol H
16.00 g O
64.00 g O
"
4 mol O !
1 mol O
180.2 g C3H6O3
108.1 g C
! 100 " 59.99% O
180.2 g C9H8O4
8.064 g H
! 100 " 4.48% H (rounded to 0.01%)
180.2 g C9H8O4
64.00 g O
! 100 " 35.52% O
180.2 g C9H8O4
1 mol C
1 mol C9H8O4
!
"
b. 5.00 ! 1024 C atoms !
6.022 ! 1023 C atoms
9 mol C
0.923 mol C9H8O4 (aspirin)
1 mol C9H8O4
4 mol O
6.022 ! 1023 O atoms
c. 7.50 g C9H8O4 !
!
!
"
90.08 g C9H8O4
1 mol C9H8O4
1 mol O
1.00 ! 1023 O atoms
6.65 a. 9 mol C !
61
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Chapter 6
1 mol H
1 mol C9H8O4
6.022 ! 1023 molecules C9H8O4
!
!
"
1.008 g H
8 mol H
1 mol C9H8O4
1.87 ! 1023 molecules (aspirin)
d. 2.50 g H !
6.66 a.
b.
c.
d.
0.066 mol CaCO3
6.6 ! 1021 calcium ions
3.4 ! 1021 magnesium atoms
2.3 ! 1021 hydroxide ions
3 mol O
" 0.750 mol O
1 mol Mn2O3
1 mol MnO2
2 mol O
!
" 0.460 mol O
20.0 g MnO2 !
86.94 g MnO2
1 mol MnO2
0.750 mol O $ 0.460 mol O " 1.210 mol O
6.022 ! 1023 O atoms
" 7.287 ! 1023 O atoms, or 7.29 ! 1023 O atoms
1.210 mol O !
1 mol O
1 mol MnO2
1 mol Mn
54.94 g Mn
b. 20.0 g MnO2 !
!
!
" 12.6 g Mn
86.94 g MnO2
1 mol MnO2
1 mol Mn
2 mol Mn
54.94 g Mn
!
" 27.5 g Mn
0.250 mol Mn2O3 !
1 mol Mn2O3
1 mol Mn
12.6 g Mn $ 27.5 g Mn " 40.1 g Mn
6.67 a. 0.250 mol Mn2O3 !
6.68 a. 115 g Cl
6.69 a.
b.
c.
d.
b. 0.914 mol P
C5H5N5 % 5 " CHN (empirical formula)
FeC2O4 % 1 " FeC2O4 (empirical formula)
C16H16N4 % 4 " C4H4N (empirical formula)
C6H14N2O2 % 2 " C3H7NO (empirical formula)
6.70 a. NH2
b. C2H2O
c. CrCl3
d. C8H8NO
1 mol S
" 0.0686 mol S (smaller number of moles)
32.07 g S
1 mol F
" 0.411 mol F
7.81 g F !
19.00 g F
0.0686 mol S
0.411 mol F
" 1.00 mol S
" 5.99 mol F : 6 mol F
0.0686
0.0686
Empirical formula " SF6
1 mol Ag
b. Moles of Ag " 6.35 g Ag !
" 0.0589 mol Ag (smaller number of moles)
107.9 g Ag
1 mol N
" 0.0589 mol N
Moles of N " 0.825 g N !
14.01 g N
1 mol O
Moles of O " 2.83 g O !
" 0.177 mol O
16.00 g O
6.71 a. 2.20 g S !
0.0589 mol Ag
" 1.00 mol Ag
0.0589
0.177 mol O
" 3.01 mol O
0.0589
Empirical formula " AgNO3
62
0.0589 mol N
" 1.00 mol N
0.0589
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 63
Chemical Quantities
1 mol Au
" 0.453 mol Au (smaller number of moles)
197.0 g Au
1 mol O
" 0.681 mol O
10.9 g O !
16.00 g O
0.453 mol Au
" 1.00 mol Au ! 2 " 2.00 mol Au
0.453
0.681 mol O
" 1.50 mol O ! 2 " 3.00 mol O
0.453
Empirical formula " Au2O3
c. 89.2 g Au !
6.72 a. SnF4
b. N2O5
c. AlPO4
6.73 a. In 100 g of compound, there are 76.54 g C, 12.13 g H, and 11.33 g O.
1 mol C
" 6.373 mol C
Moles of C " 76.54 g C !
12.01 g C
1 mol H
" 12.03 mol H
Moles of H " 12.13 g H !
1.008 g H
1 mol O
" 0.7081 mol O (smaller number of moles)
Moles of O " 11.33 g O !
16.00 g O
12.03 mol H
6.373 mol C
" 9.000 mol C
" 16.99 : 17 mol H
0.7081
0.7081
0.7081 mol O
" 1.000 mol O
0.7081
Empirical formula " C9H17O " 9 ! 12.01 $ 17 ! 1.008 $ 1 ! 16.00 " 141.2 g
282 g (molar mass)
" 2.00
141.2 g (mass of empirical formula)
2 ! (Empirical formula C9H17O) " Molecular formula C18H34O2
0.895 g C18H34O2
1 mol C18H34O2
6.022 ! 1023 molecules
!
!
"
b. 3.00 mL !
1 mL
282.4 g C18H34O2
1 mol C18H34O2
5.73 ! 1021 molecules of oleic acid
6.74 a. 9.85 g
b. FeS2
c. 0.0820 mol Fe
6.75 In 100 g of compound, there are 40.7 g C, 5.12 g H, and 54.2 g O.
1 mol C
" 3.39 mol C
Moles of C " 40.7 g C !
12.01 g C
1 mol H
" 5.08 mol H
Moles of H " 5.12 g H !
1.008 g H
1 mol O
" 3.39 mol O (smaller number of moles)
Moles of O " 54.2 g O !
16.00 g O
5.08 mol H
3.39 mol C
" 1.00 mol C
" 1.50 mol H
3.39
3.39
3.39 mol O
" 1.00 mol O
3.39
1.00 mol C ! 2 " 2.00 mol C 1.50 mol H ! 2 " 3.00 mol H 1.00 mol O ! 2 " 2.00 mol O
Empirical formula " C2H3O2 " 2 ! 12.01 $ 3 ! 1.008 $ 2 ! 16.00 " 59.04 g
118 g (molar mass)
" 2.00
59.04 g (mass of empirical formula)
2 ! (Empirical formula C2H3O2) " Molecular formula C4H6O4
63
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Chapter 6
6.76 Empirical formula " HgClO3; Molecular formula " Hg2Cl2O6
6.77 Moles of C " 1.65 ! 1023atoms C !
1 mol C
" 0.274 mol C
6.022 ! 1023atoms C
1 mol H
" 0.548 mol H
1.008 g H
1 mol O
Moles of O " 4.39 g O !
" 0.274 mol O (smaller number of moles)
16.00 g O
0.548 mol H
0.274 mol C
" 1.00 mol C
" 2.00 mol H
0.274
0.274
0.274 mol O
" 1.00 mol O
0.274
Empirical formula " CH2O; Molecular formula " CH2O ! 4 " C4H8O4
Molar mass " 4 ! 12.01 $ 8 ! 1.008 $ 4 ! 16.00 " 120.10 g
Moles of H " 0.552 g H !
6.78 Molecular formula " SrO6Cl2
6.79 a.
b.
c.
d.
e.
0.00680 mol NaF
4.10 ! 1021 F# ions are in the tube.
0.00197 g Na$
7.4 ! 1020 triclosan molecules are in the tube.
49.78% C; 2.44% H; 36.73% Cl; 11.05% O
6.80 The empirical formula is C3H4O, and the molecular formula is C6H8O2.
6.81 The empirical formula is Fe2Cr3O12, and the molecular formula is Fe2Cr3O12.
6.82 a.
b.
c.
d.
5.00 g gold
1.52 ! 1022 Au atoms
0.61 g oxygen
Au2O3
Answers to Combining Ideas Chapters 4–6
CI 6 a. CaCO3
b. calcium carbonate
c. 6.02 ! 1021 Ca2$ ions
CI 7 a. In 100 g oxalic acid,
1 mol C
" 2.16 mol C
26.7 g C !
12.01 g C
1 mol H
" 2.22 mol H
2.24 g H !
1.008 g H
1 mol O
" 4.44 mol O
71.1 g O !
16.00 g O
Dividing each by 2.16,
2.16 mol C/2.16 " 1 mol C : 1
2.22 mol H/2.16 " 1.03 mol H : 1
4.44 mol O/2.16 " 2.06 mol O : 2
Empirical formula " CHO2
b. Empirical formula mass " 12.01 g C $ 1.008 g H $ 2(16.00 g O) " 45.02 g EF
90. g molar mass/45.02 g EF " 2
(CHO2) ! 2 " C2H2O4 molecular formula
64
47374_06_p43-66.qxd 2/9/07 8:40 AM Page 65
Chemical Quantities
1 kg
375 mg
1g
!
!
" 27 g oxalic acid
2.205 lb
1 kg
1000 mg
100 g rhubarb leaves
1 kg
d. 27 g !
!
" 5 kg rhubarb leaves
0.5 g
1000 g
c. 160 lb !
CI 8 a.
b.
c.
d.
e.
f.
C4H8O2
C2H4O
54.53% C, 9.15% H, 36.32% O
0.464 g C
24.0 g
6.15 ! 10#3 mol butyric acid
CI 9 a. C8H14NO2
8(12.01 g C) $ 14(1.008 g H) $ 14.01 g N $ 2(16.00 g O) " 312.40 g (molar mass)
192.16 g C
b.
! 100 " 61.51% C
312.40 g
28.88 g H
! 100 " 9.03% H
312.40 g
28.02 g N
! 100 " 8.97% N
312.40 g
32.00 g O
! 100 " 20.49% O
312.40 g
c. C7H10O5
6 protons
d. 7 C atoms !
" 42 protons
1 C atom
1 proton
" 10 protons
10 H atoms !
1 H atom
8 protons
" 40 protons
5 O atoms !
1 O atom
Total number of protons " 92 protons
CI 10 a.
b.
c.
d.
e.
7.5 ! 10 #3 mol shikimic acid
59 capsules
0.046 g C
4 ! 102 kg
3 ! 104 lb
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